Gagnebina Neck. ex DC., Prodr. [A.P. de Candolle] 2: 431. 1825.

Bruneau, Anne, de Queiroz, Luciano Paganucci, Ringelberg, Jens J., Borges, Leonardo M., Bortoluzzi, Roseli Lopes da Costa, Brown, Gillian K., Cardoso, Domingos B. O. S., Clark, Ruth P., Conceicao, Adilva de Souza, Cota, Matheus Martins Teixeira, Demeulenaere, Else, de Stefano, Rodrigo Duno, Ebinger, John E., Ferm, Julia, Fonseca-Cortes, Andres, Gagnon, Edeline, Grether, Rosaura, Guerra, Ethiene, Haston, Elspeth, Herendeen, Patrick S., Hernandez, Hector M., Hopkins, Helen C. F., Huamantupa-Chuquimaco, Isau, Hughes, Colin E., Ickert-Bond, Stefanie M., Iganci, Joao, Koenen, Erik J. M., Lewis, Gwilym P., de Lima, Haroldo Cavalcante, de Lima, Alexandre Gibau, Luckow, Melissa, Marazzi, Brigitte, Maslin, Bruce R., Morales, Matias, Morim, Marli Pires, Murphy, Daniel J., O'Donnell, Shawn A., Oliveira, Filipe Gomes, Oliveira, Ana Carla da Silva, Rando, Juliana Gastaldello, Ribeiro, Petala Gomes, Ribeiro, Carolina Lima, Santos, Felipe da Silva, Seigler, David S., da Silva, Guilherme Sousa, Simon, Marcelo F., Soares, Marcos Vinicius Batista & Terra, Vanessa, 2024, Advances in Legume Systematics 14. Classification of Caesalpinioideae. Part 2: Higher-level classification, PhytoKeys 240, pp. 1-552 : 1

Gagnebina Neck. ex DC., Prodr. [A.P. de Candolle] 2: 431. 1825.

Figs 144 , 145 , 146 , 159

Type.

Gagnebina tamarascina (Lam.) DC. [≡ Mimosa tamariscina Lam. (= Gagnebina pterocarpa (Lam.) Baill.)]

Description.

Unarmed shrubs or small trees, branched from the base, 1-6 (10) m (Fig. 144M ); brachyblasts absent, perulate resting buds present, the scales striate with raised nerves. Stipules dimorphic, those on leaves formed just after the resting bud breaks striate, stramineous, similar in colour and texture to the resting bud scales, caducous, becoming subulate or setose distally on shoots, the stipule type most commonly seen on flowering and fruiting branches. Leaves bipinnate, nectaries present between the lower pair of pinnae or mid-petiole, sometimes between additional pinnae; pinnae (3) 5-40 pairs per leaf, opposite or sub-opposite, leaflets numerous, linear to oblong with truncate bases, pinnately veined, usually glabrous or ciliate. Inflorescence usually a condensed spike (a true spike in one species, Fig. 145J ), pedunculate, the peduncle often bearing a few lanceolate bracts, 1-8 in the leaf axils, the leaves sometimes suppressed and forming a paniculiform secondary inflorescence, this immersed in (or rarely exserted above) the foliage, calyx often constricted into a pseudopedicel and inflorescence appearing racemose; bracteoles subtending each flower carinate, 1-nerved; inflorescences composed of sterile flowers proximally, fertile flowers distally, and often a few functionally staminate flowers in between. Flowers with sepals and petals valvate in bud; sterile flowers with a 5-lobed calyx, fused ½-¾ its length, lobes with a central raised nerve; petals 5, free or connate, 1-nerved, staminodia 10, showy, filamentous or flattened and ribbon-like, white or rarely rose-coloured; functionally staminate flowers similar to the fertile ones but either lacking or having only a rudimentary ovary; hermaphrodite flowers similar to the sterile ones but larger, with a 5-lobed calyx and 5 free (rarely connate), usually linear or lanceolate, 1-nerved petals; stamens 10, ovate to linear, either with a terminal apiculum or lacking a gland, sagittate at the base; pollen of acalymmate 8-grained porate polyads, exine verrucate; ovary ovate, stipitate or sessile, densely strigose apically with silky white hairs, stigma punctate. Fruits either sessile or stipitate, compressed, either elastically dehiscent from the apex and recurved but not coiled after dehiscence, or indehiscent or tardily inertly dehiscent; pericarp woody in elastically dehiscent species, coriaceous to chartaceous in the indehiscent ones, the sutural ribs often greatly thickened or modified into flattened wings (Fig. 146K ), the interior of the fruit usually invaginated between the seeds. Seeds obliquely or laterally positioned, ovate to rhomboidal, with the pleurogram either U-shaped or forming nearly a complete oval on the face of the seed.

Chromosome number.

2 n = 26 ( Goldblatt 1981b).

Included species and geographic distribution.

Seven species. Madagascar, Mauritius, the Mascarenes and Comoros Islands, Aldabra (Fig. 159 ).

Ecology.

Usually along rivers in evergreen or deciduous woodlands; one species [ G. commersoniana (Baill.) R. Vig.] weedy and found in a wide array of habitats. The winged pods of G. pterocarpa have allowed it to colonise islands in the Indian Ocean; G. commersonia also has lightweight pods and in addition to being a widespread weed in Madagascar, it is found on Aldabra.

Etymology.

Named in honour of Françoise Gagnepain, French botanist (1866-1952).

Human uses.

Wood used locally for building houses, reportedly used in making Maintirano paper (Bosch et al. 2011).

Notes.

Closely related to Dichrostachys and Alantsilodendron (Fig. 143 ) and differing from these genera in having resting buds with perulate scales instead of brachyblasts, as well as having dimorphic stipules.

Taxonomic references.

Lewis and Guinet (1986); Luckow (1995); Luckow and DuPuy (2000), all with illustrations.

Figures

Figure 143. Generic relationships in the Dichrostachys clade (tribe Mimoseae). Note that the non-monophyly of Dichrostachys and Alantsilodendron has been simplified in this figure (see Suppl. material 2). For description of phylogeny and support values, see Fig. 6 caption (page 63).

Figure 144. Habit and growth forms of genera of the Dichrostachys clade A herbaceous to weakly woody thicket of shrubby Neptunia plena (L.) Benth. in seasonally inundated ruderal habitat, Bolivia (Saerkinen 2159) B, C medium-sized to large trees of Lemurodendron capuronii Villiers & P. Guinet, north-western Madagascar (Koenen 429) D small tree of Leucaena matudae (Zarate) C. E. Hughes in seasonally dry tropical forest, Guerrero, Mexico (Hughes 2153) E shrub of Kanaloa kahoolawensis Lorence & K. R. Wood cultivated, National Tropical Botanical Garden, Kaua'i, Hawaii F small treelet of Desmanthus fruticosus Rose, Baja California, Mexico (Hughes 1532) G prostrate woody suffrutex of Desmanthus acuminatus Benth., Potosi, Bolivia (Hughes 2314) H shrub of Mimozyganthus carinatus (Griseb.) Burkart, Santa Cruz, Bolivia (Hughes 2476) I shrub of Prosopidastrum globosum (Gillies ex Hook. & Arn.) Burkart, Mendoza, Argentina J shrublet of Calliandropsis nervosa (Britton & Rose) H. M. Hern. & P. Guinet, Puebla, Mexico (Hughes 1784) K small treelet of Dichrostachys cinerea (L.) Wight & Arn., Kruger National Park, South Africa L small treelet of Alantsilodendron pilosum Villiers, S. Madagascar (Luckow 4162) M treelet of Gagnebina pterocarpa (Lam.) Baill., Madagascar N shrub of Dichrostachys venosa Villiers, in dry spiny forest, southern Madagascar. Photo credits A, D-H, J CE Hughes B, C E Koenen I Estepa Patagonica K B Dupont L M Luckow M C Commenge naturetropicale N D Du Puy.

Figure 145. Inflorescences and flowers of genera of the Dichrostachys clade A Lemurodendron capuronii Villiers & P. Guinet (Koenen 435) B inflorescence of Neptunia plena (L.) Benth., basal flowers sterile with showy yellow petaloid staminodia (Wood 26650) C inflorescence of Leucaena esculenta (Sesse & Mocino ex DC.) Benth. (Hughes 1326) D inflorescences and tergeminate leaves of Kanaloa kahoolawensis Lorence & K. R. Wood E fascicles of capitate inflorescences in axils of coevally developing leaves, Schleinitzia fosbergii Nevling & Niezgoda F inflorescences of Desmanthus bicornutus S. Watson showing basal sterile flowers with exserted white showy staminodia (Hughes 1526) G capitate inflorescences of Prosopidastrum globosum (Gillies ex Hook. & Arn.) Burkart H semi-spherical capitate inflorescences of Calliandropsis nervosa (Britton & Rose) H. M. Hern. & P. Guinet (Hughes 1784) I inflorescence of Alantsilodendron ramosum Villiers J spicate inflorescences of Gagnebina pterocarpa (Lam.) Baill., the basal flowers sterile with showy white staminodia K spicate inflorescence of Dichrostachys cinerea (L.) Wight & Arn., basal flowers sterile with showy pink staminodia L compact spikes of Dichrostachys akataensis Villiers the basal flowers sterile with showy pale pink staminodia. Photo credits A E Koenen B, C, F, H, J, K CE Hughes D A Palomino E Lauren Gutierrez G D Cabral, Flora Mondocina I, L D Du Puy.

Figure 146. Fruits of genera of the Dichrostachys clade A leaves and pod of Lemurodendron capuronii Villiers & P. Guinet, north-eastern Madagascar (Koenen 429) B Neptunia plena (L.) Benth. fruits dehiscing along the dorsal suture (Wood 26650) C ripe pods of Leucaena cruziana Britton & Rose, Oaxaca, Mexico (Hughes 1300) D cluster of unripe pods on a single inflorescence of Leucaena leucocephala (Lam.) de Wit subsp. glabrata (Rose) S. Zarate, Honduras (Hughes 1557) E ripe pods of Desmanthus leptophyllus Kunth dehiscing along both sutures (Hughes 3098) F unripe fruit of Mezcala balsensis (J. L. Contr.) C. E. Hughes & J. L. Contr., held erect, Guerrero, Mexico G ripe fruits of Mezcala balsensis dehiscing from the apex along both sutures H, I unripe and ripe fruits of Kanaloa kahoolawensis Lorence & K. R. Wood, cultivated at the Olinda rare plant propagation facility, Maui, Hawaii, USA J ripe fruits of Schleinitzia insularum (Guilemin) Burkart, the valves tardily splitting along both sutures but indehiscent K winged fruits of Gagnebina pterocarpa (Lam.) Baill., Madagascar L unripe, lomentiform fruits of Prosopidastrum globosum (Gillies ex Hook. & Arn.) Burkart which break up into one- or few-seeded fragments when ripe M ripe fruits of Mimozyganthus carinatus (Griseb.) Burkart, S Bolivia (Hughes 2476) N ripe fruits, elastically dehisced from the apex, Calliandropsis nervosa (Britton & Rose) H. M. Hern. & P. Guinet, Puebla, Mexico (Hughes 1784) O unripe coiled fruits of Dichrostachys cinerea (L.) Wight & Arn. P ripe fruits dehiscing elastically from the apex, Dichrostachys venosa Villiers, southern Madagascar Q ripe fruits of Alantsilodendron pilosum Villiers, Madagascar. Photo credits A E Koenen B-E, M, N C Hughes F, G J Luis Contreras H, I A Palomino J G McCormack, Cook Islands Biodiversity K, P, Q D Du Puy L I Specogno, Flora Mendocina O Atamari (CC-BY-SA- 3.0).

Figure 159. Distribution of Gagnebina based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.